(1) Field of the Invention
The present invention relates to an image forming apparatus such as a copier and a printer, a power consumption restriction system for the image forming apparatus, and a power consumption restriction program and a power consumption restriction method that are executed by the image forming apparatus. The present invention in particular relates to energy-saving technology.
(2) Related Art
In recent years, the problem of environmental destruction has raised discussions about energy-saving measures in various fields. The field of image forming apparatuses such as copiers and printers is not an exception, and therefore, efforts are being made to reduce power consumption by providing image forming apparatuses with various functions. Representative examples of such functions are “preheat function” and “automatic power-off function”. With the preheat function, power supply to such a unit that has relatively high power consumption in a copier, such as a fixing unit, is reduced when a certain time period passes after the copier stops being operated. With the automatic power-off function, power supply of a copier is automatically cut off when a certain time period passes after the copier stops being operated.
At companies or the like, copiers are often shared by a plurality of departments. Some companies employ copy count management. In detail, the copy count management is realized by counting the number of copies made in every department, and charging each department with an expense that is set in proportion to its copy count.
The various functions of the copiers described above are effective energy-saving (power-saving) measures, because they can reduce power consumption while copiers are being idle. The copy count management described above is also an effective energy-saving measure, because it can eventually prevent unnecessary copies from being made regardless of users' intentions.
Also, power consumption of a copier may differ depending on a way of operating the copier. For example, when a plurality of documents are copied with the use of an Automatic Document Feeder (ADF), the total power consumption for copying the documents in a case where the documents are copied at a time (all the documents are stacked on the ADF at one time) is smaller than in a case where the documents are copied at several times, due to the difference in the copier's operating time per one document, etc. This indicates that power consumption can be reduced simply by correcting operational practices, without changing the contents of the copy operations.
The above-described copy count management, however, only involves the expense management in proportion to the copy count. This copy count management may motivate users to reduce the number of copies being made, but may not motivate users to correct the above-described operational practices for power-saving purposes.